The present invention relates to a faucet for mixing hot and cold water, and more particularly to a hot and cold water mixing faucet for selectively supplying a mixture of hot and cold water to two different passages leading to a bathtub and a shower, respectively.
Various hot and cold water mixing faucets have heretofore been proposed. For example, Japanese Laid-Open Patent Publication No. 54(1979)-78527 discloses a hot and cold water mixing faucet which includes a mixing valve comprising a fixed plate having a cold water passage hole, a hot water passage hole, and an outlet hole, and a movable plate held slidably against the fixed plate in watertight relation and having a recess for allowing or preventing fluid communication between the cold water passage hole and/or the hot water passage hole and the outlet hole. The mixing faucet also includes two on-off valves coupled respectively to two outlet passages communicating with the outlet hole, each of the on-off valves having a valve seat and a valve body movable into and out of contact with the valve seat. Mixed hot and cold water can be supplied to a desired one of the outlet passages by opening a corresponding one of the on-off valves. However, such mixing faucet is necessarily large in overall size since it requires three valves, one for mixing hot and cold water, and two for selecting the outlet passages.
There has also been proposed a mixing faucet in which a single valve is used for selecting outlet passages, in lieu of the two on-off valves as stated above. Another proposed mixing faucet employs a thermostat mixing valve having a temperature sensor which can be expanded and contracted in response to the temperature of mixed water flowing in outlet passages. In this mixing faucet, the ratio of the opening of a cold water valve in a cold water inlet passage to the opening of a hot water valve in a hot water inlet passage is adjusted on the basis of a detected signal from the temperature sensor for automatically controlling the temperature of the mixed water until it reaches a desired temperature. However, these proposed mixing faucets cannot be reduced in size because they also require two valves, one for mixing hot and cold water and the other for switching the outlet passages.